The study, led by Professor Linda McDowell at University College London, looked at who does what in the home, including managing childcare if parents work shifts.
It found that arranging childcare for families with young children typically involves as many as three or four different types of regular care.
Interviews were carried out with 139 households with at least one employed adult, including 26 single-parent households, from different economic backgrounds in six areas in London and Manchester.
The researchers said, 'Other than the most affluent households with pre-school children in each city, who tended to purchase full-time care in the market, the majority of families were dependent on complicated arrangements that needed careful scheduling across time and space, typically using three or four different forms of regular care. The smallest disruption in these arrangements is enough to precipitate a crisis.'
Professor McDowell said, 'We need to think about the ways in which different forms of care might be made more compatible and accessible, whether in terms of hours of provision, costs, or location in a neighbourhood.
'For many of those we interviewed, cost as well as quality is a key issue.
High-quality care is expensive, especially in London, and there are implications in this not only for individual parents but for those who offer a service.
'New nursery places are often short-lived as local parents cannot afford the high costs, especially when the quality of staff most parents want tends to raise the price beyond their reach.'
Amid concerns about work/life balance, the study found that 'at the bottom end of the labour market, the growing dominance of low-paid service sector work' means that many working-class women are forced to take on several jobs to achieve a reasonable standard of living.
The study, Living and labouring in London and Manchester: young adults'
work/life choices, was funded by the Economic and Social Research Council.
For copies of the report contact becky.gammon@esrc.ac.uk.